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Friday, October 9, 2015

Westinghouse announces Lead Cooled Fast Reactor initiative

On Friday, October 9, Westinghouse announced that it had launched a program to work with the US Department of Energy in the development of a new, lead-cooled fast reactor (commonly, "LFR") which would combine the advantages of lead cooling (high temperatures, primarily, as well as lower pressures) with advanced accident tolerant fuel to push the Gen-IV envelope to what it perceives as Gen-V -- a term that seems to imply the "state of the art" in perhaps 30 or 50 years down the road.

The action taken up to this point is that Westinghouse has, in acting on the requirements of the DOE opportunity, made an application to DOE for consideration as recipient of funding. These applications were due by October 5. Two awardees are expected to be named.

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Westinghouse held an exclusive blogger teleconference on this announcement and on the new LFR program with Cindy Pezze, Westinghouse Vice President, Global Technology Development and Chief Technology Officer today; more than one nuclear blogger had been invited, but yours truly was the only one who called in. As a result, the content below is an exclusive to this blog.

Pezze began by offering the observation that while Westinghouse was deeply involved in the launch of commercial nuclear power (with the PWR concept, first applied for commercial use at Shippingport Atomic Power Station, about which this author has written repeatedly) and thus has deep roots in the field, the company today is an extremely dynamic and much different looking company than it had been in the past. She pointed out the company's pride in the involvement with no fewer than three simultaneous new construction projects (the AP1000 - one site in China, two in the United States) and described these as "the most advanced PWR nuclear plants anywhere." Also mentioned were Westinghouse's venerable nuclear fuel program, and further Westinghouse's continued (if reduced) presence in the market for nuclear plant components and services. "Unfortunately, a field we have to address is decommissioning, decontamination and remediation" of closing nuclear plants, Pezze added - a field in which Westinghouse has an increasing presence as, clearly, the requirement for such work will continue to increase.

It is against this established background that Pezze contrasted the very new ("visionary," as she put it) approach by Westinghouse CEO Danny Roderick wherein Roderick challenged the Westinghouse engineers (which according to Pezze have been concentrated centrally to enable a "focus for innovation and for the enhancement of existing lines and technologies") this past February to take a clean sheet of paper and study, both from a nuclear design / feasibility standpoint as well as an economic standpoint, the various types of truly advanced reactors to "see what the future generation nuclear plant should look like." Roderick emphasized that the selected technology had to incorporate both "unparalleled safety" and "unprecedented economics."

According to Pezze, this task was vigorously pursued and all types of reactor were considered, whether cooled by gas, various metals, and even molten salts. Safety of each design was the key consideration, but economic viability (without which none could be built) was also a guiding consideration. (She noted that "the team did even look at LWR or Light Water Reactor designs for this study as well.")

The study, including some 15 or 16 criteria appropriately weighted, resulted in a rather clear winner - the lead cooled fast reactor or LFR. Pezze noted some of the outstanding aspects of this design throughout both the presentation and the Q&A portion of today's call; here, compiled, are some of those mentioned qualities:

•Inherent safety features such as reactivity feedback and high boiling point of the coolant
•Unpressurized coolant system which is inherently safer than those operating at high pressures (a pool type reactor was hinted at during the discussion, as opposed to a tank or sealed pressure vessel type)
•Coolant not reactive with air or water (as is sodium, also being pursued as a coolant in other Gen-IV designs)
•Fewer challenges with radioactive byproducts than other designs (perhaps molten salt.)

Not mentioned was the ability of such designs to assist in the disposal of spent fuel / transuranics by burning it in the reactor (appropriately processed into fuel, of course.)

Perhaps of major importance outside the electric utility field is the ability of the LFR, because of the high temperature of its coolant, to be very useful in the generation of process steam -- making economic production of hydrogen closer to reality, as well as being of benefit to industrial processes of all types. Desalination of water is also a potential use for such a plant. (The high steam quality also means that large wet steam turbines as are used at all conventional LWR nuclear plants will give way to much more common superheated steam turbines.) The high temperature steam will add the benefit of improving plant efficiency, thus plant economics. (This was one of the most pushed points of the old General Atomics gas cooled reactor program back in the 60's that resulted in two commercial but essentially prototypical plants, and no others in the US; it remains valid today, however.)

The ability of such plants to load follow was not addressed specifically on the teleconference but is noted in Westinghouse materials distributed to this writer; this is important should such a design be required to operate in concert with renewables in a situation in which the renewables have dispatch priority on the grid, and in which the LFR plant would then be expected to ramp.

Pezze observed that roughly 10 or 20 years ago, LFR projects were dropped or sidelined because materials problems appeared too daunting. However, the decades of work in metallurgy have now caught up, and the LFR appears to be a short to mid term commercial reality now.

Inside Westinghouse this program has been loosely tagged as "Gen-V," which bears some explanation. This simply refers to the fact that while Gen-IV reactors are classed as advanced designs having improved safety (above Gen-III / Gen-III+ LWR designs,) improved resistance to proliferation, reduced generated waste and improved economics, this concept by Westinghouse is hoped to provide (as noted) safety and economy on a not-yet-seen scale. Pezze observed that it's the company's belief that much of the Gen-IV technology has not been commercialized at all yet (effectively) because it's simply not economical to do so. The Westinghouse LFR project is intended to meet all the Gen-IV stipulations for overall design mentioned above, but also will be exceedingly safe and highly economical to build and operate. She described the "Gen V" label as a target out in time at which this project is directed.

(Side note, and my thoughts only: This is an interesting exercise. It essentially says that most or all Gen-IV designs are more or less a range of theoretical potential prototypes, into each of which as we all know variable amounts of money have been poured but for any of which, as conceived now, the economics are just not there. This identification that extravagantly expensive and highly technically idealized nuclear plants will not get built may be a key, so far as this writer is concerned, to the success of Westinghouse's program. We might well refer to the "technically ideal" fluid fuel, aqueous homogeneous reactors that died a difficult and well deserved death commercially in 1959 after which they were supplanted in all quarters of research and commercial construction by "less ideal" concepts which actually could get built and operated. Keep in mind these are my observations, not those of Westinghouse or anyone associated with it. Now back to the story.)

A key factor in safety for this new LFR program is noted by Pezze as being the use of advanced accident tolerant fuels, on which Westinghouse has been working and which have an increasing focus. On the other end of the promise is economy - which Pezze points out is largely due to the fact that the primary coolant system is unpressurized, allowing components to be smaller and/or less expensive because they quite simply can be made thinner. Having a non-reactive coolant (with water or air) also means simplification of plant safety systems as compared with other technology choices which embrace a reactive coolant to obtain other characteristics. (To this writer, this move appears to be right in line with Westinghouse's continued desire to simplify nuclear plants, dating from the AP600 era and working right through to the present AP1000 and now, apparently, beyond.)

Pezze's description of the selection process included the thought line that if one selects a high pressure design of plant (NSSS or Nuclear Steam Supply System) then the protections against radioactive release from the plant get more complicated and expensive -- and of course the actual materials of the NSSS get thicker, heavier and more expensive. Adding to these costs by using a reactive coolant (such as sodium) drives cost up even further. Now, given that much research has been done on the use of lead in nuclear power as a coolant, and that Westinghouse feels that with dedicated work the materials problems can be solved in the short to mid term, then all these cost increases as described above are "off the table." In other words, some advanced reactor design choices add a sort of self-inflicted cost and complexity increase over the LFR for no practical advantage.

So what are the next steps? Pezze says that within several months the DOE announcement of who will be awarded the funds to develop an advanced design is expected, although no firm date is known. Westinghouse is working with 12 different parties, said to be national labs and universities but cannot name them all specifically just yet (although that is coming eventually in a future press release; we'll have to wait and see.) The DOE FOA is a five year program and we can expect further announcements and developments through that time frame.

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There you have it. Westinghouse has thrown its hat back into the advanced reactor field (it was once quite seriously in that field, as it was the lead reactor vendor for the Clinch River Breeder Reactor project.) The design chosen has all the hallmarks, at least as presented to me today by Westinghouse, of something that may not be the furthest up the scale of "theoretically ideal" designs, but which can and will get built. The notion that Westinghouse will focus on extreme safety AND extremely economical cost for the plant tell me that the company is paying attention to what the entire world is saying about nuclear energy -- and that Westinghouse also knows we need nuclear energy for many, many years to come. One more thing - a big "thank you" to Westinghouse for reaching out to the nuclear blogging community.

I'm speculating they mean austenitic titanium and niobium-stabilized steel (instead of zirconium) cladding. Combination with the nitride (instead of oxide) fuel is nice to have but the technology gap is more in the cladding than in the pellet material. Remember the news where US DOE funds got allocated to accident-tolerant cladding materials after Fukushima? I guess they took so long to find out it won't work in the thermal spectrum so now it's back to the future with lead cooling.

If memory serves, the Soviets built some lead cooled reactors for submarine use, but had trouble with the lead reacting with some of the materials.That said, Russia too is working towards building a lead cooled fast reactor, the BREST-300. The gating item is the nitride fuel, currently being tested in the BN-600 fast reactor.